1. Field of the Invention
The present invention relates to the field of power storage unit charging devices.
2. Prior Art
Many battery powered devices such as hand-held and other portable devices currently include a universal serial bus (USB) port for connecting to other devices having a universal serial bus port, such as hosts, powered hubs and bus powered hubs, for communication with a host or local area network. Being battery powered, these hand-held and other portable devices require their batteries to be charged periodically, typically through an AC to DC converter plugged into an AC source. Such battery chargers work well, though are inconvenient to carry around with the battery powered device, particularly as the battery powered devices themselves become smaller and smaller and easily carried on ones person.
Universal serial bus powered battery charger primarily intended for use in battery powered hand-held and other portable devices to charge the battery or batteries within the battery powered device when the same is connected to a host device, powered hub or a bus powered hub through a universal serial bus (USB) port. The battery charger includes one or more current limits to conform to the universal serial bus current supply limit set in the USB specification. Any of the universal serial bus voltage and current limits may be used to charge batteries in the battery powered device, such as single cell lithium-ion batteries. Various features are disclosed.